Hydraulic differential transmission



Nov. 30 1926.

A. w. GROTE l HYDRAULIG DIFFERENTIAL TRANSMISSION Filed .Sep'ql 5, 1920 3 Sheets-.Sheet 1 @5% -Iftolwtmf Nov. 30 1926.

A. w. GRO-r:

HYDRAULIC DIFFERENTIAL TRANSMISSION 3' Sheets-Sheet 2 Filed sept. s; 1920 2 ,0 ad I H 1 y y IIII. Ill...

Filed Sept. :5, 1920 y 3 Sheets-Sheet y3 F/'Illgn @YM f, 'Ml/4770 /vfra Cil Patented Nov. 3o, 1926.

UNITED STATES Lei-nalin?.

PATENT OFFICE.

ALFRED w. GROTE, or BROOKLYN, NEW YORK.- 'l

H'YDRAULIC DIFFEBEN-D-IAL TRANSMISSION,

Application led September 3, 1920. Serial No. 407,854.

Hydraulic transmissions of certain types have been proposed but have been unsatisfactory and impracticable because of their cost, complications and ineiiciency. In accordance with the present invention the hydraulic transmission for the purpose spec' ified has been reduced to its simplest form,

comprising generally a centrifugalpump on the propeller shaft, water wheels on the live axle sections, vchannels for directing the liquid from the centrifugal pump to the water wheels for propulsion thereof, and controlling valves for regulating the'iilow of the liquid through said channels for propulsion of the Wheels in either direction. For practical considerations the `elements are mounted in a one-piece casing which jis closed by suitable plates adapted to be bolted in place or removed with comparative facility. In the casing are cast the liquid channels by which the compartments for the respective wheels are connected andthe bearings for the @ions shafts the valve members can be cast integral with Athe cover plates making altogether a simple and inexpensiveassemhly. Otherobiects of the invention will appear withgreat'er particu-` larity as the descriptioproceeds. reference being now had to the accompanying drawings for a detailed description of one simple practical embodiment of the improvements. In the drawingsvFigure 1 is a view in plan ofthe improved transmission .showing Aits application as a final drive for motor vehicles. 'parts being.`

broken away to show details of construction. Figure 2 1s avlew 1n rear elevatidn of the transmission shown l1n Figure 1, parts being Figure 3 is a view in longitudinal section 3-3 of Figure 1 and looking inthe direction of thevari'ows. l

Figure 4 is a view in perspective showing, somewhat schematically, the casing for the transmission and the channels formed therein 4to afford ,communication for the fluid between the respective pump and water wheels.

As will be understood by one -skilled. inthe art, the hydraulicntransmis'sion to be describedcan be adapted for use under any conditions where there is a propeller shaft and a pluralityof'driven shafts as between which lprovision forl differential movement s yto bemade. However,A the most'useful lield of application vof thepresent improvements will probably be found in the automobile art where it canbe employed advantageously las the final drive: for transmitting the powerfromthe propeller'shaft to the two live, axle sectionsof the drive wheels. lm-

wportant features of. construction in the embodiment have 'been made particularly with reference to such an' application, it being necessary in automobile practice, of course,

to conform to certain requirements of size,

weight, accessibility, etc.

As 'shown most clearly in Figure 3, there is cast or otherwise formed, preferably as an integral unit, the housing a provided in itsl front andrear wallsfwith recesses a', a2 respectively, and in its sidewalls Awith recesses a?, at, indicated in dotted lines in Figure 1.v The top wall a"A and the bottom wall a can be formed integral with the housing-g. Certain channelsare formed in? theA walls, of the housingto placecertain ofthe recesses, such as .a.,` .a3,-I.and a?, ai, incommunication, for transmission ofthe liquid.,

in a mannerto described-,andfthese channels can belarran'ged at-wliateve1jf oints and in whatever form"7s"eems,e 'cient for their purpose. f linxjjlhefl ,illustrated Aembodivment there isformedachannel a7 in the upper yright hand'portionlof the front wall of the housing v`a, this,lchannelapoinmunicating with the recess a and withl'therrecess a3 and being generally inclined*'downwardly,

so thatv thev liquid 'discharged'l-from it into the recess a3 will take a generally downward path.v `Adjacentthe lower left. hand portion of the rearjwall-ofthe housing a there is formed a -chann'el'a,indicated in dottedq lines in Figurefl, which., places the recess a2 in ,communica-tion `,with the recess a, this channel extending generally upwardly, so as to 4discharge the liquid into the recess a4 in a generally upwa'rd direction, as indicated by the upwardly pointing arrow in Figure 2. Adjacent the upper right hand portion'of the rear wall of the housing a is formed a. channel a which places the recess ar? in communication With the recess a3, this channel extending generally downwardly, so as to discharge the liquid in a generally downward direction into the recess c3 to cause a rotation of the paddle wheel in a direction contrary to the direction of its rotation from the flow of the liquid through the channel a7 into the recess a3.

The liquid is contained within the housing in a tank section al", which may be of generally cubical form and made up of the several walls of the housing a hereinbefore described7 and this tank communicates through openings au, an, als, a formed respectively in the four side walls of the tank with the recesses aQat, c3, a4, respectively. The openings a and an12 may be circular and formed on the longitudinal axis of the tank, while the openings a. and a are preferably formed in the presentembodiment near the bottom of the side walls.

The propeller shaft for a motor vehicle is indicated at b as extending through the opening a in the front wall of the housing and through the opening a12 in the rear wall thereof. This propeller shaft has keyed thereon a centrifugal pump c which is of such form and dimensions as to rest rotatively within the recess a', and also has keyed to itV adjacent its rear end a centrifugal pump alwhich rests rotatively within the recess a2.

Within the recess a3 is mounted rotatively a water Wheel e which is keyed on one of the axle sections e', and in the recess a* is mounted rotatively a water wheel f keyed on the other live axle section f.

The recesses a', a? can be closed by cover plate 51,. h., forming a convenient liquidtight closure for the housing. The cover plate (7 may have formed therewith a'bearbe closed liquid-tight by a nut g2 forming a stuffing box, While the rear cover plate h may carry therewith a bearing h for the rear end of the shaft b. The side plate may, if desired, be formed' integral with thc axle tube z" and have formed therewith a bearing 2 for the axle section e', while the other side plate f: may be secured to the axle tube k andhave formed therewith a bearing 7112 fo. the other axle section f.

The tank is filled with any suit-able liquid, such as oil, this oil having free access to the recesses a', a2'through the openings a, a. Rotation of the propeller shaft b will cause the blades of the respective pumps c, (l

`to pick up thevoil and throw it out centrifugally into `tlie respective channels a?, as.

The oil will be discharged by these channels tangentially into the recesses a3, a4 and iinpinge on the blades of the water wheels e, f, so as to drive these wheels for forward propulsion of the vehicle. Circulation of the oil back into the tank 4al" is completed through the openings a, a in the opposite side walls Normally, with equal resistance offered to rotation b v the axle sections e', f', the two wheels c, f will be driven at equal speeds. If, now, one or the other of the axle sections e', f offers more or less resistance according to the traction conditions, the water wheels e, f will be rotated at a differential speed dependent upon such relation of the resistances.

lf, now, the channels a7, as be closed and the channel a? opened, the liquid will be forced into the recess a and impinge on the blades of the Wheel e so as to drive the wheel in a reverse direction, thereby driving the vehicle backwards. For accomplishing this control of forward speeds and reverse, suitable valves can be employed. The valves for controlling the channels a7, as may be of any suitable type, such as gate valves, and are indicatedconveniently at Z. m, respectively. In Figure 2 .valve m is shown indotted lines as a gate valve extending across the passage as. Valve Z is a similar valve and both these valves are connected by links Z. m respectively to an operating rod n, the link m being pivoted on a bracket h2 to. the plate h and t-he link Z being pivoted to a bracket g3 on the plate g. The channel a may be controlled by a valve indicated at o connected through a link o to an operating rod 02, the link o being pivoted to a bracket h3 on the plate. h. By operating the rod n, the valves Z, m may be opened to any desired degree or may be entirely closed. By operating the rod 02 the valve o can be opened to any desired degree or closed. In this Way, the vehicle can be driven forwardly or rearwardly and the size of the given openings in the channels controlled so as to E v give different speeds in either direction. ing r1 for the propeller shaft b adaptedl to It will be evident that many changes can be made in details of construction while preserving the principle of operation.

I claim as my invention:

1. The combination with a propeller shaft and oppositelyy disposed driven shafts, of a hydraulic differential transmission comprising a housing, bearings for the propeller shaft in opposed walls of the housl ing, bearings vfor the driven vshafts in opposed walls of the housing respectively, re cesses formed in the walls of the housing, centrifugal pumps carried on the propeller shaft and disposed in recesses in opposed walls respectively, paddle wheels carried on the ends of the driven shafts respectively, and disposed within the respective recesses in the housing Walls, a tank for liquidv communicating with the pump recesses ax- 'ially of the pumps and with the paddle 4Wheel recesses adjacent the perimeter thereof and channels formed in the Walls of the housing for leading liquid from the periphery of the pumps to the periphery of the paddle wheels. j

2. The combination With a propeller shaft and oppositely disposed driven shafts, of,

spectively, paddle Wheels carried on theX ends of the driven shafts respectively, and disposed within the respective recesses in the housing walls, a tank `for liquid communicating with the pump recesses axially of the pumps and with the paddle wheel recesses adjacent the yperimeter thereof and channels formed in the Walls of the housing for leading liquid from the-,periphery of the pumps to the periphery of the paddle Wheels to drive `the paddle wheels in` one direction and channels formed in the walls of the housing for leading liquid from the periphery of the pumps to the periphery of the paddle wheels for driving the paddle Wheels in an opposite direction. l

. The combination with .a lpropeller lshaft and oppositely disposed driven shafts, of a hydraulic differential transmis* sion comprising a housing, bearings for the propeller shaft in opposed walls of Ithe housing, bearings forthe driven shafts in opposed Walls'of'the. housing respectively, recesses lformed in thevwalls of the housing,l centrifugal pumps carried on the propeller1 shaft and disposed -in recesses in opposed walls respectively, l.paddle Wheels carried on the ends of the driven shafts respectively, and disposedvvithin the respective recesses in the housin Walls, a tank for liquid communicating Witi the pump recesses axially of the pumps and with the paddle wheelv recesses adjacent the perimeter theretrol the flow of liquid shafts carried by the of, channels formed in the wallsjof the housing for leading liquid from the periphery" t e paddle of the pumps tothe periphery of Wheels to drive the paddle Wheels in one direction, channels formed in the walls of the housing for leading liquid from the periphery of the pumps to the periphe of the paddle wheels for driving the padd e wheels in an opposite direction, and valves to conthrough the channels. v v

4. In combination with a. propeller shaft and oppositely disposed' driven shafts, a hydraulic differential transmission comprising a housing having recesses formed in its front and rear Walls, a centrifugal pump mounted xedly on the propeller shaft in each recess, the wall of each recess lbeing formed with an opening to place the central portion of said pump in communication with the interior of the housing, a Water tjs,

wheel -secured to the driven sha respectively, said housing being formed in each opposite side Wall with a recess to receive a Water Wheel the Wall of each of t e lastJ named recesses being formed with a open- .the pumps to the periphery of the water wheels respectively lto drive said wheels in the opposite direction, cover plates for all ofthe recesses bolted to the housing, bearings for the propeller shaft and driven plates, valves carried by the plates tocontrol the flow of liquil through the channels, operating means for the valves controlling the flow of liquid in the first mentioned channels 'and separate operating means for the valves controllincr the iiowof liquid in the second mentioned channels.

This specification signed this 2d day ot vSeptember A. D. 1920.

ALFRED W. GROTE. 

